Drill rod and bit joint



m. m F,

M. HoKANsoN Jan. 3l,

Patented Jan. 31., 1939 UNITED STATES DRILL ROD AND BIT JOINT Martin Hokanson, Duluth, Minn., assignor to Eidco, Inc., a corporation of Minnesota Application February ze, 1937, serial No. 1121.958r

4 claims. (ci. Z55-s4) This invention relates to improvements in percussion drills and has special reference to such in which the drill head or bit is detachable, it having a relatively short shank having a smooth tapered m bore for frictional contact with a similarly tapered terminus of the drill rod for operating same so that the bit ls held tightly thereupon by friction.

. The principal object of the invention is to provide 4a connection between the drill rod and bit that will transmit the forces of the blows from the drilling machine through the drill rod to the cutting edges of the bit in amore perfect manner than heretofore known.

Another object of the invention is to provide a connection betweenthe drill rod and bit which will eliminate breakage of collar of bit as well as the end of the rod.

A further object of the invention is to provide a connection between the rod andbit that is more secure than any connection heretofore known, to increase the drilling speed.

A still further object of the invention is to provide a connection between drill rod and bit which is more easily and quickly applied or removed and l, one more economical to construct than any connection heretofore known, and one that will not loosen during operation.

' Further objects and advantages of the invention will appear in the following description a@ thereof.

. Referring now to the accompanying drawings, forming part of this application and wherein like reference characters indicate like parts:

. Figure 1 is a central vertical section of a drill -35 rod, in this instance hexagonal in cross section,

having an improved form of cutting head attached thereto, and a novel form of means for removing said head.

Figure 2 is a reduced plan view of the U-shaped ,m wedge used for removal of the head fromthe rod. Figure 3 is a section on theline 3 3, Figure 6. Figure 4 is a section through the rod on a plane with the top of the shank of the bit. Y

' Figure 5 is a plan View of the cutting face of w the bit.

Figure 6 is a view similar to Figure 1 of a modied formo! rod and bit assembly. y,

Figure 7 is a sectional view on the line '1 -fl oi' Figure 6.-

a modified provision for convenient separation/of the bit from the rod by the wedge.

l represents the drill rod having the axial bore t therein, as is usual in such forms of drills, and 3 is the cutting head orbit, which. in this instance,

l il Figure 8 is a view similar to Figurel showing is provided with a downwardly and inwardly tapered bore indicated at I, and the proper taper of which constitutes a principal part of the invention, the same being not to exceed 10 from the axis of the bit, and which has been determined by 5 actual practice to function ideally in constituting a rm union betweenthe end of the drill rod and the bit, and one which will not turn in drilling, nor liable to accidental dislodgment under any normal circumstances, yet which may be easily 10 and quickly removed with a hammer and by the novel means here disclosed.

' This novel means consists of a ring indicated at 5 which is pressed or otherwise forced onto the tapered shank of the rod the proper distance l5 above the upper terminus of the bit shank when applied to the rod for insertion of a wedge shaped member indicated; at 6 and being of U-shape (see Fig. 2) for convenient application into the space between the ring and the shank of the bit and ao functioning equally on both sides when driven 'to force the rod and bit apart.

It is to be understood that the taper oi the rod in Fig. 1 whether at an angle of 10 or less, as previously stated,A continues upwardly from the lower terminus of the rod until merging with the outer circumference of the rod to provide the proper transmission of shock absorption without fracture of either rod or bit shank; this being, as before stated, one of the principal objects of the invention.

If preferred and possibly adaptable to some classes ofwork, the equivalent of the buttress ring may be accomplished by upsetting the end of the rod to form a buttress shoulder l; thisdnodiiication being illustrated in Fig. 8. In the modified form shown in Figures 6 and 7 it will be noted that a iiat inclined seat d is formed on opposite sides of the shoulder 9 of the bit it so that the wedging member illustrated in Figure 2 a@ of the drawings may be forced intermediate of this -shoulder and the at annular bottom of the drill rod I l for separating the head from the rod, funcmening in a like manner to that showin in Figure i of the drawings, and thus avoiding the necessity of M a ring as illustrated at 5, Figure l, attached to the drill rod or forged thereupon as previously stated;

the frictional contact of the rod to the bit ld occurring in the tapered union between the inserted shank l2 of the bit into the end of the 5@ rod.

Having thus described my invention, what ll claim and desire to secure'by Letters Patent, is:

1. A drill rod and bit joint, characterized by the bore of the skirt of the bit and the end of the rod ring and the drill bit for separating the rod and bit.

3. In a drill rod and a drill bit frictionally applicable thereto, a fiat surface on said bit, a at surface on said rod, one of said surfaces b eing inclined to the axes of the bit and rod when united, and wedge means insertable between said surfaces for separating the bit from the rod, said wedge means having;v opposed flat surfaces in planes coincident with the planes of the fiat surfaces on the bit and the rod.

' 4. A frictionally unitable drill rod and bit of the class described, lsaid rod having a flat terminal surface at right angles to the axis thereof and the bit having opposed at surfaces upon either side of the axis thereof, characterized by the flat surfaces on the bit being inclined at an angle to the axis thereof, and wedge means having opposed at surfaces in planes coincident with the planes of the surfaces on the bit and the rod.

MARJIIN HOKANSON. 

